Semiconductor display devices used in portable electronic appliances have been required to reduce an area other than a pixel portion (i.e., to narrow a bezel width). A system-on-panel obtained by forming a pixel portion and some of or all driver circuits over one substrate is one of effective means for achieving a narrow bezel width.
Patent Document 1 described below discloses a system-on-panel display device in which a display portion and peripheral circuits are formed on one substrate.